LONDON, ENGLAND—According to a Science News report, archaeologist Tomos Proffitt of University College London and primatologist Tiago Falótico of the University of São Paulo have found changes in the patterns of stone tool use over a period of 3,000 years in capuchin monkeys living in northeastern Brazil’s Serra da Capivara National Park. Excavations in the park have also uncovered tools made by humans, but Proffitt explained that the ancient tools in question, which were dated by association with pieces of charred wood in each of four sediment layers, more closely resemble those made by modern capuchins living in the park. The changes in the tools over time probably reflect changes in local vegetation, Proffitt added. The tools include rocks used as platforms for pounding objects, partial and complete pounding stones, and pieces of rock that detached from the tools during pounding. Smaller, more heavily damaged stones dated to between 3,000 and 2,500 years ago are thought to have been used to smash open seeds or small fruits with soft rinds. Larger stones, dated to about 300 years ago, may have been used to open hard-shelled fruits and nuts. Slightly smaller pounding stones began to be used about 100 years ago. Proffitt said the capuchins use similar stones today to crack open cashews. For more on artifacts produced by capuchins, go to “The Monkey Effect.”